Computer performance issues are a headache. This problem drags down your entire PC, yet the cause can be mysterious, as there are thousands of software bugs, drive issues, and other issues that might cause a slow computer.
While this article is written with Windows 10 in mind, these solutions are generally applicable to Windows 8.1, 8, 7, and even Vista.
Thankfully, there's some good news. You can root out the cause of a slow computer out with comprehensive solutions. These will narrow down the possible cause.
How to Fix a Slow Computer
These solutions are arranged from the least to most disruptive, so it's best to follow them in order. There's no need to reinstall Windows if your slow computer is the result of too many open browser tabs. Also, skipping steps might hide the real cause of the problem.
Restart your computer. This step will eliminate any one-time bugs or software conflicts that cause slow performance and provide a clean slate for additional troubleshooting.
You might be tempted to skip this step. Don't! It can solve your problem in a few seconds with minimal effort.
Close browser tabs, and don't open more than a few at once. Browser tabs can begin to tax system resources, especially RAM, as your computer attempts to organize data from numerous websites so you can quickly view it when you return to a tab. Closing tabs can provide an immediate boost on PCs with 4GB of RAM or less.
Open Task Manager by pressing Ctrl+Shift+Esc simultaneously, and be sure to click the "more details" drop-down arrow at the bottom of the Task Manager window. Look for tasks that are using more than 50% of your PC's CPU or memory resources. To close a task, right-click the task and then click End Task. Read our advanced Task Manager guide to learn more about this useful utility.
Check your power settings and turn off power-saving mode. Windows PCs typically ship with settings that prioritize performance, but it's possible to change the default settings by mistake. This is particularly true of laptops, which often slip into power-saving mode to conserve battery life.
Improve your Wi-Fi signal. The problem you perceive as a slow PC might be a spotty internet connection. You can check this with an internet speed test. Poor Wi-Fi will make websites load slowly, message services lag, and cloud storage services fail.
Search for and halt any large downloads or uploads on your computer. Downloading or uploading a file can consume a surprising amount of processor and storage resources on older PCs. Halting the file transfer should provide an immediate improvement if this is the culprit.
Cloud storage services are the most likely cause of excessive file transfers, as they download and upload files automatically in the background.
Turn off Windows' unnecessary visual effects. Windows uses shadows and animations to make the operating system look modern, but these effects can slow down some Windows PCs. Turning them off might give your system the boost it needs.
Enable Windows ReadyBoost. This feature can turn an external USB storage device into a home for temporary storage, which is similar to upgrading your computer's RAM, though not quite as effective. ReadyBoost is a great way to use an old USB thumb drive.
If this solution works, it's a sure sign your computer needs more RAM to perform its best. Consider upgrading your RAM soon.
Free up space on your hard drive. Windows, and other installed programs, use space on the hard drive to store temporary files that they can quickly access later. A packed hard drive makes this onerous or impossible, which reduces performance.
This solution asks you to delete applications and files, which you might not want to do. Moving files to a free cloud storage service is a simple, fast solution that will free up space without deleting files you'd rather keep
Delete temporary files. In some cases, the temporary files Windows uses to improve performance can grow too large, consuming too much hard drive space and slowing performance.
Reduce or change startup programs. Many programs, like online messaging services or cloud storage services, start automatically when your computer boots. These programs often run in the background, so you might forget they're installed.
Update Windows. A new version of Windows may fix a bug causing your performance problems. Windows Update can also install new drivers for your PC's hardware, which often improves performance.
Install an antivirus program. Malware can cause your computer to slow by using system resources to perform tasks behind the scenes. This usually won't be obvious in Task Manager because malware is often designed to hide from prying eyes.
An antivirus program can find malware that's causing performance issues, but antivirus programs can be demanding on system resources, as well. You may need to uninstall the antivirus program if it seems to worsen performance.
Defragment your hard drive. This is rarely required on a modern PC, which is why it's near the bottom of this list. However, the list of possible solutions is starting to grow slim, so it's worth a shot before trying the final and most dramatic options.
Reset Windows using the operating system's built-in utilities. This option is nearly as effective as a clean reinstall, which is the final solution we'll offer, and much easier to perform. This will fix your performance issues if they're caused by a bug or configuration issue in Windows itself.
Resetting or reinstalling Windows will remove most or all locally stored files on your PC. Be certain that you've backed up files you want to keep.
Perform a clean reinstall of Windows. If all else fails, reinstalling Windows is your final hope. A complete reinstall will remove absolutely everything on your computer, including most (but not all) malware that might've snuck into your hard drive.
My Computer Is Still Slow. Now What?
The solutions in this guide are exhaustive. If your computer is still slow, then the computer is either too old to run modern software well or has defective hardware causing a performance problem. You'll need to take your computer to a repair shop for further troubleshooting or consider a newer, faster PC to replace your current machine.